The present invention generally relates to pneumatic braking systems for railway trains, and in particular to pneumatic braking systems for locomotive consists.
A train consist for freight transportation includes at least first and second adjacent locomotives, directly connected with each other, followed by a plurality of interconnected cars or wagons. The very first locomotive of such a consist is named the lead locomotive, whereas the at least one further locomotive of the consist is named a trail locomotive.
In modern trains for freight transportation each locomotive of such a consist is provided with an Electronically Controlled Pneumatic Brake System (hereinafter referred to as the ECPBS) and a brake control handle device installed in the driver's cab provides electric control signals to the ECPBS in accordance with the commands by the train driver.
The current state of the art in American freight railways operation, despite the coming introduction of the new ECP (Electronically Controlled Pneumatic) technology and the long lasting Radio Distributed Power technology (the Locotrol” system of “General Electric”), is still mostly based on train consists formed of multiple adjacent locomotives pulling a plurality of connected cars, wherein the whole train braking effort is exclusively managed by the ECPBS of the lead locomotive, controlling the pressure in the brake pipe extending through the whole train consist, according to the electric signals from the brake handle of the lead locomotive. According to the pressure variations, the pneumatic brake system of each wagon or car will individually apply a retardation effort contributing to brake, slow down and stop the whole train.
In case of a critical failure occurring in the ECPBS in the lead locomotive, the whole train can result unable to properly brake, requiring procedures and actions to rescue the train, or to replace the failing lead locomotive with an efficient one, for instance by exchanging the positions of the lead and the trail locomotives.